Christopher Hunter Cosby was arraigned in Multnomah County Circuit Court on Friday following his arrest Thursday.

A neighbor reported seeing Cosby on his back porch hitting his dog with a wooden baseball bat "with enough force that she did not think the dog would survive the beating,'' deputy district attorney Nicole Jergovic wrote in a probable cause affidavit filed in court.

A Troutdale police officer spoke with the suspect's girlfriend, who supported the neighbor's account.

When arrested, Cosby admitted he "beat the (expletive) out of it,'' referring to the dog, the affidavit says.

But Cosby denied he used a bat.

"I just lost it, but as hard as he bit me I could have been justified in grabbing my knife and gutting the damn thing,'' Cosby told officers, according to the affidavit.

According to Cosby, he was outside with the dog and slapped it on his hind quarters. The dog turned around and bit his hand, causing severe pain. That's when he struck the dog in the head with his closed fist, he told officers.

Cosby turned over a wooden bat from his bedroom, and police noticed a red smear on it that resembled blood, the affidavit says. A Multnomah County animal services officer took the dog into custody.